Method For Workpiece On-line Test Based On Spatial Filtering

As the rapid development of manufacturing, more advanced detect technique and means for products are required. On-line test, dynamic test, numeric control and automatic measurement are becoming the trend. On the other hand, processing of massive information on the production field is made possible because of the improvement of PC hardware and the application of brand-new sensors. Convert optical image of measured workpiece into digital signal using proper device, then obtain numeric value related to measured workpiece under further analysis, the test efficiency and adaptability can be improved obviously.In this dissertation, a workpiece on-line test method based on spatial filtering is proposed and the workpiece auto-grading processing system is accomplished by combining MCS-51 single chip microprocessor (SCM) and universal serial bus (USB) etc.In this method, both of the standard workpiece and tested workpiece are placed on the input plane of optical processing system symmetrically, while a sine grating which precisely shift 1/4 grating period is set on the spatial spectrum plane, the subtract output optical field distribution of these two workpiece is obtained on the center of the output plane. By filtering out the part of subtract output by a visual stop through a minification optical system the intensity signal that only carry the difference between these two workpiece is detected by photronic cell, after I-V conversion, preamplification, clamping and A/D converting, the workpiece error...